Cometic v. MLS
Thread Starter
TECH Fanatic
Joined: Dec 2001
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From: Germantown, MD
Cometic v. MLS I'm looking for head gaskets. I know I read a thread somewhere recently that listed the different gasket thicknesses and told you what your subsequent C/R would be. Does anyone have this info?
What's the difference between cometic and MLS?
Thanks,
Mike
What's the difference between cometic and MLS?
Thanks,
Mike
TECH Senior Member
Joined: Nov 2001
Posts: 11,603
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From: Chi-Town, IL
I'm running cometics on my setup, I would rely on them to lower the compression as much as the heads......get some 73cc 5.7L or 6.0L heads, that will drop you down to under 9.5:1 comp.....
Cometic gasets are MLS (multi-layered-steel)
on newer models Gm uses a MLS gasket, these mls (stock thickness) are cheaper then cometics gaskets
so only get cometics if you need a special thickness.
on newer models Gm uses a MLS gasket, these mls (stock thickness) are cheaper then cometics gaskets
so only get cometics if you need a special thickness.
Before you run out and by mls gaskets, you need to inspect your heads. 98-00 heads had a notch in the side of the head. Visible from outside the motor.
They look like a place to pry the head off of the block with a prybar. If you have the notches and use the mls gaskets you will leak coolant. Every 98-99 I looked at had the notches. About 50% of the 2000's I looked at had the notches. I guess mid year 2000 GM deleted the notches that they say don't exist. If you have the notches run the cometic gaskets.
They look like a place to pry the head off of the block with a prybar. If you have the notches and use the mls gaskets you will leak coolant. Every 98-99 I looked at had the notches. About 50% of the 2000's I looked at had the notches. I guess mid year 2000 GM deleted the notches that they say don't exist. If you have the notches run the cometic gaskets.
Anyone else have any info on how the 99 heads leak with the MLS gaskets?
Doesn't make anysense to me how it would matter unless it was an unperfection in the deck/head mating surfaces. I really haven't looked at my car to notice this notch though.
Doesn't make anysense to me how it would matter unless it was an unperfection in the deck/head mating surfaces. I really haven't looked at my car to notice this notch though.
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Thread Starter
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Joined: Dec 2001
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From: Germantown, MD
Originally Posted by smokinHawk
IF i read right bushman is getting 6.0 heads (01-03 aluminum) so the notches wouldnt matter in his cas, but if somebody else does with stock 98-99 heads yes.
Does anyone know where I can find prices on these Gaskets? How about info on subsequent C/R for the varying thicknesses?
Mike
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Originally Posted by HUGGER ORANGE SS
Good point 30thta436
How is that G-Trim holding up to the 70,000 impeller rpms??
Clint
How is that G-Trim holding up to the 70,000 impeller rpms??
Clint
The engine is another story. Broke another piston and cracked the block. I found the limit of the stock fuel pump and t-rex fuel system. I was running out of fuel over 6400 rpms and it detonated again. I have the engine out of the car again. I have another block I'm assembling. I also am getting rid of the t-rex and stock pump and running a dual intank setup, I built. I hope to have the car running tonight or early in the morning. Then I will dyno tune again tomorrow, then the track on Sunday. Thats the plan at least.
How is your ATI holding up. Last I saw you broke 600RWHp.
Originally Posted by Tiago
Anyone else have any info on how the 99 heads leak with the MLS gaskets?
Doesn't make anysense to me how it would matter unless it was an unperfection in the deck/head mating surfaces. I really haven't looked at my car to notice this notch though.
Doesn't make anysense to me how it would matter unless it was an unperfection in the deck/head mating surfaces. I really haven't looked at my car to notice this notch though.
By the way I have seen 2000 f-bodies with the notches in the head. I have also seen some 2000's without the notches. So I imaging that there was a casting change somewhere mid 2000.
https://ls1tech.com/forums/showthrea...hlight=notches
TECH Enthusiast
Joined: Aug 2003
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From: Downers Grove,IL
just use the Cometics or the MrGasket brand MLS.
I am using the Mrgasket MLS. Part #3143G.
They look like Cometics, embossed sealing areas and full nitrile coated.
Sell for about 65$ each through Summit.
I have 98 heads and yes they have the notches.
Steve
I am using the Mrgasket MLS. Part #3143G.
They look like Cometics, embossed sealing areas and full nitrile coated.
Sell for about 65$ each through Summit.
I have 98 heads and yes they have the notches.
Steve
30thta436... Man how many times are you going to pop something in your motor??? This is the 3rd time right?
You will like the duel Walbro pump setup..
The car is running strong with 602 rwhp and 11psi..
Clint
You will like the duel Walbro pump setup..
The car is running strong with 602 rwhp and 11psi..
Clint
Originally Posted by HUGGER ORANGE SS
30thta436... Man how many times are you going to pop something in your motor??? This is the 3rd time right?
You will like the duel Walbro pump setup..
The car is running strong with 602 rwhp and 11psi..
Clint
You will like the duel Walbro pump setup..
The car is running strong with 602 rwhp and 11psi..
Clint
Sounds like we have about the same cars except yours is ATI and mine is Vortech. Do you think you can get any more out of the blower, or is it tapped. How much are you over spinning it now?
I spun mine to about 67,000 impeller rpms. The blower is holding up very nice. If I spin my blower up more I'll need to buy another Cogs pulley which will run me about 75 bucks.. Sure I could do that, just have not yet. My 112 LSA Cam is hurting my numbers.
Clint
Clint
Originally Posted by HUGGER ORANGE SS
I spun mine to about 67,000 impeller rpms. The blower is holding up very nice. If I spin my blower up more I'll need to buy another Cogs pulley which will run me about 75 bucks.. Sure I could do that, just have not yet. My 112 LSA Cam is hurting my numbers.
Clint
Clint
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Joined: Nov 2001
Posts: 11,603
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From: Chi-Town, IL
I was thinking about the whole pulley changing thing........the thing that will hold us back from making the pulley size changes is the availability of the COG belts in certain sizes, the 73T 31T I'm currently running like Jeremy uses a 37" belt and the tensioner pulley has to be put under the belt instead of over to make it fit......
I'm sure I'll spin the blower to the max..........and then some
I'm sure I'll spin the blower to the max..........and then some
Originally Posted by BIGBOS
I was thinking about the whole pulley changing thing........the thing that will hold us back from making the pulley size changes is the availability of the COG belts in certain sizes, the 73T 31T I'm currently running like Jeremy uses a 37" belt and the tensioner pulley has to be put under the belt instead of over to make it fit......
I'm sure I'll spin the blower to the max..........and then some
I'm sure I'll spin the blower to the max..........and then some
What kind of power is it making?